We continue our series on “modern persistence” with an important topic: “callbacks.” Callbacks are little hooks into the lifecycle of your data model so that you can be notified or take action when something changes. We will first explore the “Active Record” pattern of callbacks, popularized by Ruby on Rails, and then see how we can improve upon them.

How does our SQL-based solution for persistence compare with modern SwiftData? We put things to the test by rebuilding our complex @FetchAll query using @Model and the @Query macro!

We finish a sneak peek of our upcoming Structured Queries library by showing how queries built with the library can be reused and composed together, and how we can replace all of the raw queries in our application with simpler, safer query builders.

We want SQLiteData to work seamlessly behind the scenes without you having to worry about how it works, but we also wanted to make sure you had full access to everything happening under the hood. Let’s explore the secret sync metadata table to see how we can fetch and even join against data related to sync, including sharing information and more.

We add iCloud sharing and collaboration to our reminders app rewrite, so that multiple users can edit the same reminders list. It takes surprisingly little code, no changes to our feature’s logic, and handles all manner of conflict resolution and more.

We introduce a new feature to our reminders app: cover images for each reminders list. This pushes us to create a brand new database table to synchronize, and allows us to demonstrate how SQLiteData seamlessly handles binary blobs by converting them to CloudKit assets under the hood.